Bittersweet
by solitaryloner
Summary: Because love is a bittersweet poison, capable of driving any man mad. And when someone goes mad, no matter how well they hide it, they will never be quite the same - so it's dangerous to let your guard down, you poor, unfortunate girl, because you don't know what he'll do to ensure that you won't leave his side. For Kagamine Rin 2002. LenXMikuXRei. Rated T for murderous intentions.


_**Solitaryloner: **__I'm clearing out all my one-shot requests…so you guys can probably expect a bunch of new stories these couple of days. But the stories are all completed since, you know, they're one-shots, so don't worry about me not completing them as usual, etc._

_This is a one-shot request for Kagamine Rin 2002. Yandere!LenXMiku. There will be a minor pairing of ReiKu too, so I'll find a way to work this into the plot…_

* * *

Love was a bittersweet emotion. At least, that was what it was like, from his personal experience. Love was sweet at times, but at other times, it could be horribly bitter…

He had every right to be jealous, or perhaps in a sense he had no right – because she was supposed to love him, and only him. If there was no one else she was meant to fall for, then surely that meant he would not have to worry about her leaving him, right?

But no, that was so, _so _wrong. That wasn't anything like what reality showed him. Though he knew that she was his, and solely his, Fate seemed to think otherwise. She fell in love with someone else, and not only did that hurt him, but he also _knew _that deep inside she had to be suffering. How could she be happy when she was with someone who was not him, regardless of the bright smiles she showed, the happiness evident in their eyes? He knew that, in the deepest parts of her mind, she _knew _all this was wrong.

So he would help her get rid of this wrong. She never knew how much he suffered, watching her in so much pain that it was oblivious to all but him, the friend who was closest to her. They were, after all, childhood friends, and he knew everything there was to know about Miku Hatsune – he knew things about her that she herself was not aware of, and that made him suffer on her behalf. Like this, like now…so miserably ignorant.

He watched from behind the tree, his gaze alighting on the happy couple – happy to all but the eyes of him – and felt a sharp pang of pain go through his chest, like the very sight was enough to break his heart physically. People always claimed that when hearts broke, it was nothing more than a pain of the mind, and that life would go on once there was no more attachment to the cause – but he knew otherwise. He knew that when hearts broke, people broke too, and no matter how much time had passed they would never be whole again. That was why people tried so hard to brush away broken hearts.

His heart wasn't broken. Well, not yet anyway. And he was determined not to let it break, let it shatter into hundreds of tiny little pieces, the way it would if he allowed his childhood friend and love to continue with such self-torturous folly. Why could she not see that this Rei Kagene was not the right person for her? She always bemoaned the fact that there was no one out there suited for her – then what of him? Was he not the best match for her – did they not like the same things, share the same thoughts, share everything…? Everyone had always assumed they would be together, but _she _never did.

In her eyes, he would never be anything more than a friend – a dear friend perhaps, but still nothing more than that. His lips twisted down into a harsh frown – it was silly of her, to continuously deny what everyone could see as inevitable. One day, she would come to him, realising that there was no one else better suited for her than _him. _But until then, Rei Kagene filled all her thoughts, and his patience was fast thinning. Perhaps he would have to do something more drastic to push her away from him. He could hardly bear waiting anymore, when he knew that this would just end up hurting her.

_His _Miku could never be allowed to be hurt in any way, not even by his own hand, let alone by someone as undeserving as Rei. He scoffed at the sight of the raven haired boy, his hands resting lightly on her shoulders, his forehead leaning against hers – inside, he shook with blind rage. _What right does he have to steal what is mine?_ As if Rei did not already have enough of his own. They were cousins, the two of them, and Rei always got the best things – he was richer, and he could have anything he possibly ever wanted.

But he would not give up Miku to his cousin. He could give Rei anything else the boy desired, but Miku was untouchable territory, dear and precious to him – and Rei, the one who already had so much more than him, the one who could have anyone and anything he wanted – decided that he wanted the one person he would never want to give up. _Why does he always have to compete with me…is he trying to prove he is better?_

He would gladly concede that his cousin was better, would have been willing to give up anything to Rei Kagene, so long as the boy left Miku well alone. But _no,_ he had not, and now he was getting desperate. Initially, he had not cared that his cousin and his best friend were getting interested in each other – he thought that it was nothing more than a casual, passing infatuation, and that soon enough the both of them would move on. That was the only reason why he had been willing to help her get to know him, help her with her interest in his cousin, and end up making the worse mistake of his life.

He had not expected them to actually get together, go on dates, officially announce that they were a couple…and he most definitely had not expected this relationship to last any longer than a month. But it had, everything had defied his expectations, and he started to regret not interfering sooner. Miku never had time for him anymore. She was always with Rei, always doing couple stuff, never bothering to notice the dejection in her friend's blue eyes as she walked away with Rei, off to do things without him…

Honestly, he had felt neglected. Her constant absence in favour of Rei's company made him feel listless and useless – he felt like he wasn't good enough for her, which was probably why she had wanted Rei's company instead of his own. She probably thought – the same way everyone else did – that his cousin was _so much _better than him in every aspect. Was that why she liked Rei instead of him, despite him knowing her for longer?

Even when they invited him along, he felt like the third wheel, and usually the awkwardness he felt around them would intensify until he could not prevent himself from leaving, stating that he had other things to see to. She would protest weakly at his leaving, for which his heart would flutter slightly in happiness, but ultimately she would return her attention to her _boyfriend_, and his heart would sink back down in his chest.

The whole school knew they were together, and they always bothered him about news regarding their favourite couple – Rei and Miku looked perfect together, students always claimed, and he honestly thought that they really had nothing better to do if all they were ever interested in was gossip regarding their relationship. And they always badgered _him _about news because, as they claimed, he was Rei's cousin and Miku's best friend – who else were they supposed to go to for stories about Rei and Miku together?

It broke him a little inside every time someone asked him cheerily about how Rei and Miku were doing. He always just put on a bright smile and gave a carefully positive answer, and the person would leave satisfied, but inside his mind and heart the actual negativity he felt would take root and blossom into something he could not quite control. There was rage, jealousy, spite – all the different curses which made up a noxious, toxic concoction of negativity and disillusionment. _They're not meant to be!_

He had to get rid of Rei. Yes, Miku would leave him by herself eventually, that he was certain, but he was getting impatient. He ought to catalyse their separation – and what better way was there to do so other than to remove his cousin from the picture? His teeth gritted, and his fingers clenched into fists – he would get rid of Rei so that Miku would finally be clear and pure, the way she was supposed to be, without anyone clinging on to her like a leech the way his cousin did. His lips tilted up into a smirk.

And after that was done, when she was alone again…she would be all his once more. The only question was how he was going to remove Rei without making it seem suspicious, and how he would avoid drawing attention to himself. _Well, that's simple enough._

* * *

Miku could not shake off the feeling that someone was staring at her. She whipped around, her gaze scanning the area sharply, but she was no one and nothing suspicious. Slowly, she turned back to face the front, but her heart wouldn't stop racing in her chest.

"What's wrong?" Rei whispered, slender fingers reaching out to tilt her face towards him. Her heart thudded again, this time in a far more pleasant way, as she met his honey coloured eyes – his gaze was as soothing and caring as usual, and as she stared into his eyes she felt like she was going to melt into a gooey puddle. "You've been on edge the whole morning. Don't like spending time with me?" he teased, lips tilting upwards.

"No, of course it's not that," she stuck her tongue out playfully at her boyfriend, and he flicked her nose, an equally mischievous gesture. Her joviality died down as she recalled the piercing stare she had been feeling upon her, ever since she and Rei arrived at the park an hour ago. It was normal for the two of them to just come to this park, the place where he had first confessed to her, sit on a bench and just talk about everything and anything under the sun. It was a familiar and simple ritual they had, and normally she enjoyed it very much – but she couldn't, not when her back prickled the way it did now.

"Then what is it?" he immediately asked, concern layering his smooth voice. She closed her eyes briefly, just enjoying the sound of his voice – it was as soft and rich as velvet, caressing her lightly with his warmth and care. "You haven't been acting quite like yourself ever since we got here. It worries me," he leant a little closer, his gaze flicking from side to side as he studied her face, trying to discern what the problem was.

She decided to tell him the truth – he had always known when she was lying to him, anyway. "I feel like someone is…watching me," she said softly, lowering her voice because she felt like if she spoke too loudly, the watcher really would reveal himself. And she was rather unsure about how she would react if this stalker did come to her – on one hand she wanted to know who it was and why they were doing this. But on the other hand she was absolutely terrified to know. _Maybe it's just me being paranoid?_

Rei glanced around the park at her words, his eyes narrowing. His gaze flitted back to her. "I don't see anyone suspicious," he echoed her earlier thoughts, wariness suddenly filling his golden eyes; he knew that Miku would not make a big fuss out of nothing, and if she claimed that she felt like someone was watching her, then there was probably something about this place today which was unnerving her. Miku laughed shakily.

"Perhaps I am overthinking things," she shrugged lightly, trying to brush her concerns away. "We're out here to enjoy ourselves and I shouldn't be so jumpy about it," her lips tilted up into a semi-forced smile, as the gaze she felt on her seemed to pierce through her body – _but where is it coming from? _"Do you want to go somewhere for lunch?" she hastily drew his attention away from the matter at hand, appealing to his insatiable appetite for good food. Rei hesitated, clearly still worried about her, and she waited.

Finally, he shook his head almost imperceptibly and laughed, his eyes closing. "Whatever you want, Miku," he pinched her cheek gently, and she brushed his hand away, her forced smile becoming more genuine. "Do you want to try that new café down the street? They say the place sells excellent parfaits," he said cheerily, motivated as ever by the prospect of food. Especially desserts – Rei had a really sweet tooth.

"Oh, sure, I'm up for anything," she rose from the bench, brushing herself down, and Rei followed suit. He was just a little bit taller than her, and he was a little sensitive about their height difference – he knew he was a little on the short side – but she thought it was cute, and she never hesitated to tell him otherwise. She turned to the direction they had to walk in, and her eyes widened as she saw a familiar head of blond hair.

"Len!" she yelled, waving excitedly as she jumped up and down, trying to attract the blond-haired boy's attention. Len's head instantly whipped around at the sound of her voice, trying to find her – his blue eyes alighted upon her and he grinned, a bright, almost blinding smile, and then he was coming over to her and Rei, hands tucked casually into his jeans pockets. She wondered what he was doing outside today.

Len usually preferred to spend his weekends sleeping in, or maybe playing video games with his sister, Rin Kagamine. It was a rare sight to see him out and about this early on a Saturday – not that it was early, but Len's weekend mornings basically started in the late afternoon. This was considered the middle of the night for him. "You're up early," she commented when he reached them, his blue eyes twinkling with familiar humour.

"Well, so are you two," he answered, looking from her to Rei, a huge yawn interrupting him as he spoke. He covered his mouth with his hand; his other hand stretched out towards them in a gesture of apology, before he shook his head and blinked, trying to become more awake. "Mother sent me on an errand. We're running out of milk at home," he shrugged, before scowling playfully at Rei. "And all that since Rei dropped by two days ago and decided that he wanted to make milkshakes at our house."

"Hey, your family enjoyed the fruits of my labours too," Rei shot back, a similar grin to Len's on his face. Miku enjoyed listening to the two of them talk – they were cousins, and their banter was ever something to be enjoyed. "But you're right; I _was_ the one who used up all the milk in your house…" Rei mused to himself, ignoring Len's arched eyebrow. "So I should pay for your milk!" he finally decided, much to both her and Len's surprise – Len gaped at his cousin, blinking his blue eyes in what appeared to be shock.

"Oh, there's really no need to…" her friend said hastily, drawing back from Rei, but Rei just shook his head, absolutely insisting on paying for the milk. Finally, Len relented, and Miku watched in amusement as the blond boy grudgingly took hold of the money Rei gave to him. Len pocketed the grocery money, tiredly rubbing the back of his hand against his eyes. _He must be really tired. _"What are you two lovebirds up to now?"

"We're going to have lunch," she answered, watching Len's gaze drift over to her. "Do you want to join us?" she offered immediately. Len paused, seeming to consider, and she wondered if he even had the appetite to eat lunch – it was obvious that he hadn't woken up too long ago. Unlike her, Len had never been a heavy eater, and he usually picked at his food more than actually eating it. Half the time, whenever she invited him out for a meal, he would decline, saying that he would rather stay home and sleep than eat.

Len was a really heavy sleeper… "Sure, fine, I'm okay with anything," he shrugged lightly, much to her surprise. "We're having guests over now," he rolled his eyes at her and Rei's questioning looks. "So even if I go back, Mum will just expect me to entertain the visitors, and that's worse than eating I guess," he shrugged again, tucking his hands back into his pockets, "which is pretty much why Rin is out with Rui at the moment."

Rui Kagene was Rei's sister. Rei was typically quite protective of his sister, but given that he hadn't reacted in any way when Len mentioned her going out, Miku figured that he must have known beforehand. "Well, I guess they'll enjoy themselves. Aren't the two of us together now as well, cousin?" Rei asked mischievously, slinging his arm around Len's shoulders. Len was just a tiny bit taller than Rei, not that the difference was obvious. Miku knew Rei was still quite sensitive about that difference, however.

"You make it sound like we're on a date," Len sounded faintly disgruntled, shrugging Rei's arm off. "And you're neglecting your girlfriend. Come on Miku, lead the way to wherever we're going for lunch," he diverted the attention back to her, and she blinked, feeling a little dazed – she had just been following Len and Rei's conversation, and frankly she had forgotten what they were going to do before Len had arrived.

"Oh, lunch! Yeah, lunch," she muttered, more to herself than to the other two. Still, they heard her, and they both shot her an odd look, which she ignored. "We were going to that new café down the street. The one that just opened last week?" there was no sign of recognition in Len's eyes, and that didn't surprise her in the slightest bit, since Len was basically an idiot when it came to knowledge about new eateries and cafes, etc.

"Whatever. I don't think I'm going to eat anyway," he yawned again, his fingers reaching up to ruffle his own blond hair – Len Kagamine was sixteen, the same age as her and Rei, but he most certainly didn't act his age. Nor did he look it – he looked slightly older, at eighteen perhaps, and she figured that was because of his features. He was – though she admitted this rather grudgingly – _extremely _handsome, with those sharp, princely features, his bright blond hair and those narrowed eyes that reminded her of sapphires. All that, coupled with his lean and lanky build, made him look a little older than he really was, and she guessed that was one reason why so many girls crushed on him.

God, she lost track of how many classmates had come up to her, asking her excitedly about Len's relationship status. _Girls, calm down, he's still single…_yeah, and she had no idea why he was still single, since basically he could attract anyone he wanted to. She did not know how he managed to grow any taller than her when he barely ate, but that was probably a genetic thing and she didn't want to question it too much.

Rei, her boyfriend, looked a little like Len, which wasn't too surprising since they were related after all. He was every bit as good-looking as his cousin, and some days she could still hardly believe that he had asked _her _out, of all girls – that he had indicated interest in her, when she wasn't really in his social circle or anything like that. Heck, she was surprised he even knew her name – yet he had liked her, he had been interested enough in her to actually ask her out, and…here they were, still together after a month despite what she had thought at first. It was all thanks to Len and his help, she knew.

Len had helped her to get closer to his cousin. He had known for ages that she _might _just have a crush on Rei – _just _a really tiny one – and he had offered to help her get to know him. Of course, at first she had been really shy about it – wouldn't that be really strange? But Len insisted otherwise, dragging her to his house whenever Rei dropped by or something like that. She was _really _grateful to Len, because if it wasn't for his help and his constant support, there was no way she would have been with Rei today. She would still be the shy girl, well-liked but not popular, who stared at the king of the school from afar, wondering if he even knew of her existence. _I owe Len far too much._

Len was her best friend since childhood. They knew each other in preschool, and they had pretty much stuck together ever since. It was during a preschool activity – drawing, she remembered, when they were told to draw a picture of where they thought they would be ten years from then – that they realised that they were similar. They had both envisioned themselves having a job, and that job…well, they both wanted to be lawyers.

That similarity sparked interest, so they started hanging out, and all these years later they were still close. They weren't neighbours or anything – Miku lived closer to their high school than Len did – but whenever she had time, she would come over to his house, and he would gladly welcome her…provided he wasn't sleeping at the time, of course. She had no idea how he managed to do so, but Len was perfectly capable of sleeping for sixteen hours a day, only rising from bed when it was night-time.

"Shall we go?" Rei's voice cut into her reverie as she continued staring at her best friend, who was looking around the park – _probably startled by what it looks like in the morning, since he's never awake before two, _she snickered to herself. "I'm getting really hungry," Rei complained, nudging her shoulder. She tossed him a casual smile before leading the way out of the park, the two boys trailing after her like lost puppies. Her stomach let out a quiet growl, and she quickened her footsteps, wanting to reach the café before the lunch crowd came flooding in. She didn't want to have to wait around for a table.

As she walked, she shivered slightly – it wasn't cold at all, but she couldn't help feeling like there was someone watching her again, eyes boring into the back of her head. Yet, when she discreetly looked behind, again she couldn't see anyone suspicious around. She met Len's startled blue gaze and smiled at him before turning back to face the front, her heart racing in her chest, her mind awhirl with panicked thoughts.

The only people behind were Rei and Len, so why did she keep feeling like there was someone watching her…someone making her feel trapped and vulnerable, like she was a mouse and they were cats just waiting, _waiting _for the right moment to pounce?

* * *

Rei Kagene wondered why he was still sitting here, watching his girlfriend laugh heartily with his cousin. He wondered why they had even invited Len along.

It wasn't that Rei disliked his cousin or anything like that. Len was a fun guy to be with, provided he wasn't half-dead from insufficient sleep at that moment or anything like that. It was just that…well, it was just that Miku and Len knew each other for far longer than Miku and Rei, and frankly Rei felt a little left out when the two of them exchanged some kind of inside joke, both of them bursting out into laughter at something he did not understand. Though he and Miku were boyfriend and girlfriend, Len would always be closer to her than he ever would be. It wasn't an idea he particularly liked.

But it wasn't like he could do anything to change that sentiment. They had known each other since their childhoods – he only knew Miku for what, two years? And they had been together for only slightly over a month. It was no surprise that Rei was still finding out new things about her that Len had known for years – but he didn't like going out with both his girlfriend and his cousin, because sometimes it felt like he would never be close enough to Miku. He would never be as close to her as Len was, and that…hurt.

_Yeah, yeah, I know. Boyfriend does not necessarily equate to best friend, I know that. _In his mind, he knew that, but no matter how clichéd that sounded his heart said otherwise. Rei liked Miku, might go so far as to claim that he loved her – for he did feel very, very strongly for her, and didn't want to consider the possibility of her not returning his feelings – but he would always have to fight for space in her heart. Fight with his cousin, who could have any other girl he wished to have…he already had Miku as a best friend, so why couldn't Len just let other guys have a chance with her?

"I'm going to dump this ice cream all over you, Len!" he heard Miku screech, jerking him out of his thoughts – Len and Miku were sitting next to each other, and Miku was waving an ice cream spoon at the blond boy, who held his hands up to protect his head from her semi-joking threats. Rei wondered what had happened before this to set off the whole threatening thing. His own chocolate parfait sat sadly before him, largely untouched – he had barely eaten anything since arriving at the café, because he couldn't stop himself from thinking about Len and Miku. If anyone didn't know better, they would assume that Len and Miku were the couple, and he was the third wheel lagging behind them.

"Could you please just stop?" Len whined exaggeratedly, earning himself a giggle from Miku. "You're being a public nuisance. Don't you agree, Rei?" his cousin suddenly turned to him to ask, and Rei jolted up in his seat, startled by the fact that they had bothered to include him in their private little conversation. Or perhaps not so private – he was fairly certain that the table next to theirs could hear everything Miku and Len were saying.

"Um, I don't know…" he kept his answer neutral, not quite wanting to get himself involved in this conversation, since he knew he wouldn't have any idea what the two of them were talking about. Miku pouted, which earned her a light blush from her boyfriend, before she reached over to punch him lightly in the shoulder.

"You're supposed to disagree with him!" he smiled weakly at that, wishing that he could somehow just disappear from this place. _It's not that I have anything against Len, really. It's just that…why did he have to appear? Why did we have to run into him? Every time we go out and he comes along, I always feel so excluded, even though I'm Miku's boyfriend. _It almost made him feel like a substitute of some sort, and that feeling was further exacerbated by the fact that he and Len were _cousins _– they even looked like each other.

"Aren't you eating your parfait? I thought you liked chocolate," his attention was taken by Len now, who was gazing at the barely-eaten dessert in front of Rei. True, Rei _did _like chocolate, but his appetite was gone. He didn't feel like eating anymore, not while watching Len with his girlfriend. They looked meant for each other – they got along so well, and he knew that Len could make her laugh whenever she was upset, which was something Rei was not necessarily capable of doing yet. He didn't yet know her well enough – there were many things about Miku which he had not found out about.

He actually wondered if she would ever reveal that much of herself to him. If Len already knew all her secrets, would she be willing to bare her heart to someone else? There had to be a limit to how many people could know her, wasn't there? Rei was aware that he was behaving like a whiny, spoilt brat who was forced to share his most favoured possession, but he couldn't help himself – he hated being put through this.

"Not hungry," he murmured, lacing his fingers together and propping them under his chin. Miku had long finished her waffle, and Len his banana split – they were now just waiting for him to finish _his _dessert, and Rei could honestly say that the very thought of eating now made him want to throw up. His stomach felt like it was stuffed with cotton. Miku frowned at what he said, and before he knew it, the teal haired girl had picked up the dessert spoon stuck in the parfait, scooping up some of the rich chocolate cream.

"Open your mouth," she ordered, cupping her hand under the spoon so that none of the cream would spill out on the table. He shot her a look of confusion, and she sighed, shaking her head – "You can't just not eat, not after we paid for all this food – it's so expensive!" the last part was said in a whisper, and Rei's lips tilted up into a crooked smile. It was the smile he put on when he didn't _want _to smile, but the situation required him to do so – and he guessed Miku didn't know that yet, because she just continued to wave the spoon at him. He sighed a little, but willingly parted his lips.

As his girlfriend fed him, his gaze slid over to Len. Len was watching them, a neutral look on his face – but there was something about his narrowed eyes that Rei didn't quite like, and he wondered if Len was jealous. Their gazes met, and Len and Rei simply stared at each other, neither one of them quite able to read the other's expression. Finally, Len looked away from him, and Rei found that he could breathe again, though he didn't feel very comfortable about what had just passed between the two of them.

There was a certain look on Len's face which he hadn't been quite able to identify, and that was rather strange for Rei since the two of them knew each other since childhood. There was nothing about Len that Rei didn't know – well, perhaps there were a few things – but generally, Rei knew his cousin enough to guess what he was thinking simply by the look on his face. This time, Rei could not read his cousin's thoughts, and that unnerved him quite a fair bit. It made him wonder what Len was thinking.

It made him wonder if Len was jealous, and to what extent the blond would be willing to show that jealousy. As he watched Len from out of the corner of his eye, Len twirled his dessert spoon around, his long fingers idly playing with the handle of the spoon – and then he jabbed the spoon down into the empty bowl which had held his ice cream, the spoon making a harsh grating sound as it scraped against the glass. Rei flinched – Miku did not respond to what Len was doing, intent as she was upon making him finish his food – and Len raised his head to stare outright at Rei again. This time, though Len's face was still carefully blank, Rei couldn't help the little tremor of fear that ran through him.

And he knew he had to be careful, because now he was realising that he didn't know his cousin as well as he thought he might, and there was no way to tell what Len was going to do, not when he was being like this. _I really shouldn't let my guard down._

He had never been suspicious of Len before, but when the boy was looking at him this way…he didn't think he could just relax either. He knew Len felt strongly about Miku, and had long had his suspicions that Len might like her – he just hadn't expected this to be true, and he could _tell _Len was very fond of her – it was painfully obvious to everyone except for Miku herself, since all she ever focused on was her relationship with Rei.

He doubted that Len would actually hurt him or anything like that, especially since they were cousins. But he thought he'd better be careful, just to be on the safe side.

* * *

With that bitter smile on his face, Rei had never reminded Len of himself any more than he did at that moment. It almost made him pause as he realised that Rei was, in reality, not much different from he was. But he couldn't just stop now. He couldn't just give in.

He had given in for far too long, and he was tired of doing such a thing. He always gave Rei whatever he wanted, since Len had never wanted to strain their relationship – he was close to his cousins, after all – but why did Rei see that willingness to compromise as a free pass to take anything he wanted from Len? Even he had his limits.

Stealing his crush from him was something that definitely exceeded those limits, and Len would do anything in his power to get her back. Rei's golden eyes were filled with suspicion as they stared at each other, the painfully oblivious Miku just sitting there as the two boys fought over her, their gazes clashing so intensely that Len almost had to look away. It was painful, this staring competition they had going on. He almost wanted to give in again, but he reminded himself that he could not always back down.

Miku was important to him, and he wasn't going to give her up. _I knew her for so much longer than Rei. I can't lose her to him…the same way I lose everything else to him. _Honestly, why had he helped them to get together? If he could go back to that day he had invited her to his house, the same day Rei and Rui had come over…perhaps things would be different now. Perhaps Miku and Rei would not be together. Perhaps their mutual interest in each other would have died down. Len didn't know, nor did he want to dwell on the possibilities since what was done had already been done.

He had to get rid of Rei; he knew that was the only way he could gain his Miku back. But how could he do that? He could not kill the boy – _would not _– though secretly a part of him wanted to, wanted to watch the life bleeding out of this thief, wanted to stomp on him and scream at him and get him the _hell _out of his life, cousin or not. He just wanted Rei out of the picture, and though part of him relished the idea of slow death and murder, of making the boy wish he had never been born, the larger, more logical side of Len knew that he could not kill his cousin. Blood ties did mean something to him.

So what could he do? Len feared that one day, his psychotic, murderous side would accidentally come up and murder Rei in his sleep or something. It was a little terrifying, if he said so himself. He knew he had issues. Len knew that he ought to see a psychiatrist or something about this. But he just didn't want to – it was embarrassing to admit that he had a multiple personality disorder. Not even his sister knew about this, because he didn't tell anyone about it – hell, it had taken him forever to realise this himself.

The two different parts of his personality constantly clashed and warred, each one seeking to take control of his body, and sometimes he lost himself. Like this morning, when he suddenly blinked and woke up to find himself in the park, watching Rei and Miku from behind a tree – he had absolutely no recollection of getting out of bed and going all the way to the park, stalking the couple. He knew it must have been the _other _him who did this, who made him have the murderous thoughts, who made him wish he could just _kill _Rei so that he could be the one sitting on the bench, sitting with Miku…

He only got this personality disorder recently. Ever since Rei and Miku got together…Len guessed that he felt for Miku strongly enough that when she ended up liking someone else, he tore himself into two? He didn't know exactly, but he figured that was the best explanation he could come up with for his own behaviour. He didn't want to have this affliction, but he couldn't control his own body now, and that actually scared him. It terrified him, because he was perfectly aware that one day, he might wake up to realise that he had blood on his hands, blood on the floor, blood everywhere…

"Len?" a familiar voice shook him out of his thoughts, and he blinked, glancing across at Miku – Miku was watching both him and Rei, a faint frown on her face. "I've been calling you two for a while. Do you want to go home now? We could chill at my place – Mum said she was going to make steak with banana fritters. You know, your favourites," she added pointedly, a small smile curling her lips. It made her look truly beautiful, and Len's heart skipped a beat – hastily, he looked away from her, not wanting her to see him blush, because _nothing good _would come out of that. He looked at Rei.

Rei had not responded to her words, instead just looking at Len still. Those golden eyes seemed faintly glazed, like he was there, yet _not there _at the same time, and Len wondered if Rei shared the same thoughts he did. He wanted to let out a bitter laugh of despair – wasn't this such a cliché, with two boys both liking the same girl, and her being oblivious to the whole situation at hand? He wanted to get out of this hell, this hell he thought would only ever occur in stories and movies, the hell that was happening to him _now. _But he knew he could not – he had liked Miku for far too long to give up now.

_Knife in hand, blood on blade, palming the knife like it was a precious child – and blood, precious red liquid all over the floor, flowing like a crimson tide out of a dead body – and then he would be gone, and she would be his all over again, no one else to interfere, just the two of them…_he shook his head sharply, getting the tempting whispers of the _other _him out of his head. He couldn't keep listening to him, but he couldn't just fight the thoughts away either. He was frightened that one day, he might just slip up and give in.

There was something strangely tempting about the thought of murdering Rei. It was almost like poetic justice, to get rid of the cousin who had been stealing everything away from him since young, who had reduced his existence to nothing simply by taking Miku away – if he got rid of Rei, wouldn't Len have Miku and his reason to live back? _To remove one life and gain back another…_but no, murder was wrong and immoral, no matter how right it might seem at the heat of the moment, and logically he knew that if Miku ever realised what he was thinking, she would never speak to him again.

That didn't prevent him from fantasising about it though, and he just had to try all the harder to keep his thoughts away from his face. "Sure, I might force myself to eat a little more just for your mother's cooking," the words were semi-automatic, and Len noticed how at the sound of his voice, Rei jerked up, his attention finally returning to them. Rei nodded along with whatever Len was saying, obviously having no idea what he was talking about, and Len had to hide a tiny smirk when Miku shot him a disapproving look.

They went to pay the bill, Rei and Miku, and Len just continued sitting alone at the table, waiting for them to come back. As he waited, his heart sickening with jealousy but the plastic smile on his face revealing none of that, his hand fluttered over the various cutleries still on the table. The knives hadn't been used at all, since all they had was dessert – though Miku's knife did drip with maple syrup – and Len's fingers hesitated as they lingered over his knife, still gleaming and shining and attracting him _oh _so much –

In a moment of weakness, and a moment of gloating as he visualised stabbing Rei in the chest, red fountains spurting out – he took hold of the knife and pocketed it, the plastic smile on his face becoming a little more genuine, a little more sinister. When Rei and Miku came back to the table, their arms linked lovingly, the plastic smile stayed on his face, and they didn't think that anything was wrong. He walked behind them as they left the place, arms still linked, and he stared at their intertwined arms, his smile fading.

His hand was tucked in his pocket, and he could feel the reassuring sharp blade whispering to him, telling him that everything was fine, everything could be set right so long as he took it out and _plunged _it into Rei – it would be no different from slaughtering a chicken for food, no different from cutting a steak, its juices leaking out from the open wound, and there would be screaming and pain and fear and _everything _he enjoyed – Len gasped, shaking his head and removing his hand from the knife.

His fingers trembled, and he clenched them into a fist. He didn't know what to do. His gaze lingered on them for just a little bit longer, and he hastily glanced away, willing the _other _him to stay far, far away. He had to stop – he had to get better control of his own thoughts and feelings – and he had to stop wanting to kill Rei all the time, dammit!

If Miku ever found out about his deepest thoughts and feelings, what would she say, how would she feel, what would she think…? It wasn't something the _other _him liked to think about, because the other him didn't want to do anything which would lose her, and logically he knew that if he acted that way he would lose her. It was guilt-inducing, but Len forced himself to keep thinking of that, so he could keep the other influence from acting upon him. He had to stay normal. He was sixteen, and he was not a killer.

He just wondered how much longer he could keep this facade up before he snapped, as his eyes continued lingering upon the couple walking in front of him. Jealousy reared its ugly head in the form of dark thoughts and forbidden desires, and he gritted his teeth, unwilling to give in but falling deeper into temptation anyway. Day by day, it got harder to resist, the episodes where he would wake up to find himself somewhere completely different from where he had closed his eyes would increase in frequency, and he spent more and more time being uncertain about what his true identity was.

Was he really the normal Len Kagamine everyone knew, the one Miku had always known? Or was the real him the one he was trying to suppress all this time – the one with the knife, the one with the urge to maim and kill? He was starting to fear that the latter was the genuine him, just always sealed away without any catalyst, and now that the catalyst had appeared in the form of Rei Kagene, there was no telling what he would do. There was no telling the lengths to which he would go to keep Miku to himself.

The knife he had concealed in his pocket pricked his finger, and he winced in both surprise and pain – it was a promise, and he drew his finger out, observing the small drop of red bead on his pale skin. As he stared at the blooming drop, a dark smile flitted across his face – suddenly, the red was so bright, so mesmerising, perfect for him…

_Now, Rei __would__ look so much better with all this red colouring him, don't you think? Perhaps Miku would like him more that way. Perhaps you would be doing them a favour. _The _other _him whispered again, and this time, Len was more inclined to listen.

* * *

_**Solitaryloner: **__I could keep this as a one-shot, or I could write a second part…this one would be largely up to reader demand, I guess. Do you want this to be a two-shot, or should it stay this way? And if you want it to be a two-shot, do you want Len to give in to his darker side, or do you want him to take the high road and not kill Rei? It's all up to you readers, I suppose – so please tell me what you want, and I'll write accordingly._

_Incidentally, it's my birthday today. I just felt like mentioning that, because this is why I haven't really updated anything else today? And I had a buffet today! It was great, but I put on like, 2kg or something, so now I'm feeling a little guilty. But hey, since it's my birthday, I can indulge, right? …I'll just go running tomorrow or something._


End file.
